Actress, writer, and director Lena Dunham, of "Girls" fame, publicly announced this week on Instagram that she has endometriosis — a painful and chronic condition.

"I just wanted to let you know that, while I am so excited for Girls to return on Feb 21, I won't be out and about doing press for the new season," Dunham wrote in the Instagram post. "As many of you know I have endometriosis."

Endometriosis is a condition that affects women and refers to when tissue that would normally line...